Massive Black Hole Binary Evolution

By D. Merritt, Milos Milosavljevic. 2004

240 citations recorded by the source corpus.

Coalescence of binary supermassive black holes (SBHs) would constitute the strongest sources of gravitational waves to be observed by LISA. While the formation of binary SBHs during galaxy mergers is almost inevitable, coalescence requires that the separation between binary components first drop by a few orders of magnitude, due presumably to interaction of the binary with stars and gas in a galactic nucleus. This article reviews the observational evidence for binary SBHs and discusses how they would evolve. No completely convincing case of a bound, binary SBH has yet been found, although a handful of systems (e.g. interacting galaxies; remnants of galaxy mergers) are now believed to contain two SBHs at projected separations of <~ 1kpc. N-body studies of binary evolution in gas-free galaxies have reached large enough particle numbers to reproduce the slow, “diffusive” refilling of the binary’s loss cone that is believed to characterize binary evolution in real galactic nuclei. While some of the results of these simulations - e.g. the binary hardening rate and eccentricity evolution - are strongly N-dependent, others - e.g. the “damage” inflicted by the binary on the nucleus - are not. Luminous early-type galaxies often exhibit depleted cores with masses of ~ 1-2 times the mass of their nuclear SBHs, consistent with the predictions of the binary model. Studies of the interaction of massive binaries with gas are still in their infancy, although much progress is expected in the near future. Binary coalescence has a large influence on the spins of SBHs, even for mass ratios as extreme as 10:1, and evidence of spin-flips may have been observed.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/72c25a659680feb1445fc99941a88080dd0e2eba

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1. M. Volonteri
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Citations in the corpus

• An Eccentric Circumbinary Accretion Disk and the Detection of Binary Massive Black Holes (2006, background): “5 Department of Astronomy, University of Texas, 1 UniversityStation C1400, Austin TX 78712. gravitational radiation ultimately induces coalescence between the black holes (Begelman, Blandford, & Rees 1980; Merritt & Milosavljević 2005, and references therein).”
• The NANOGrav 15 yr Data Set: Constraints on Supermassive Black Hole Binaries from the Gravitational-wave Background (2023, background): “Once the mass enclosed within the orbit is comparable to the mass of the binary (typically at ∼parsec-scale separations), the two black holes become a gravitationally bound pair (an SMBH binary; Merritt & Milosavljević 2005).”
• The NANOGrav 15 yr Data Set: Evidence for a Gravitational-wave Background (2023, background): “…by the dynamical interactions of binaries with their astrophysical environment (e.g., with stars or gas, see Armitage & Natarajan 2002; Sesana et al. 2004; Merritt & Milosavljević 2005) or possibly by non-negligible orbital eccentricities persisting to small separations (Enoki & Nagashima 2007).”
• EFFICIENT MERGER OF BINARY SUPERMASSIVE BLACK HOLES IN MERGING GALAXIES (2011, background): “This is the origin of the “final-parsec problem” (Merritt & Milosavljevic 2005).”
• A Compact Supermassive Binary Black Hole System (2006, methodology): “The evolution of a binary supermassive black hole involves three stages (Begelman et al. 1980), which are summarized by Merritt & Milosavljević (2005) as follows: (1) As the galaxies merge, the supermassive black holes sink toward the center of the new galaxy via dynamical friction forming a…”
• Doing Science with eLISA: Astrophysics and Cosmology in the Millihertz Regime (2012, background): “The subsequent hardening of the binary orbit (phase II) is controlled by the inflow of stars from larger radii, and by the gas rotating in a circum-binary disc (Callegari et al., 2009, Colpi and Dotti, 2011, Dotti et al., 2006, 2007, 2009b, Escala et al., 2004, Merritt and Milosavljević, 2005).”
• Physics, Astrophysics and Cosmology with Gravitational Waves (2009, background): “There is considerable evidence for black hole binaries in a number of external galaxies [255].”
• HIGH ANGULAR RESOLUTION INTEGRAL-FIELD SPECTROSCOPY OF THE GALAXY'S NUCLEAR CLUSTER: A MISSING STELLAR CUSP? (2009, background): “A star passing within the orbit of the companion massive black hole will undergo dynamical interactions with the binary, which can result in the star achieving ejection velocity (Merritt & Milosavljević 2005).”
• Limiting eccentricity of subparsec massive black hole binaries surrounded by self-gravitating gas discs (2011, background): “…hardening of the binary, further inspiral is believed to be controlled by the action of either three-body scattering E-mail: croedig@aei.mpg.de of individual stars and/or the interaction of the binary with a circumbinary gaseous disc (e.g. Armitage & Natarajan 2002; Merritt & Milosavljević 2005).”